Japanese unexamined patent application publication No. 2006-25229 describes a drawing process performed by a printer driver. In this drawing process, the printer driver converts color print data to monochromatic print data when the print setting is monochromatic. First, the printer driver acquires a draw command. If the drawing instruction according to the acquired draw command is an instruction for converting print data to monochromatic data, the printer driver determines whether the print data itself is monochromatic. If the print data is not monochromatic, but color, the printer driver converts the print data to gray values. Since black text and color text are drawn in different achromatic tones as a result, the user can distinguish the different colors of the original image.
Further, recent printer drivers generally create binarized print data using an area gradation method employing a dither matrix to render print densities. The printer driver divides the print data into blocks of a plurality of pixels and applies a preset dither matrix to the block divisions to form print data.